@Override
 @Transactional
 public Relationship create(Group group, Set<Role> roles) {
   RelationshipBean relationship = new RelationshipBean();
   relationship.group(group).addRoles(roles);
   entityManager.persist(relationship);
   entityManager.flush();
   return relationship;
 }
 @Override
 @Transactional
 public Relationship create(Group group) {
   RelationshipBean relationship = new RelationshipBean();
   relationship.group(group).addRole(relationship.group().defaultRole());
   entityManager.persist(relationship);
   entityManager.flush();
   return relationship;
 }